Additive manufacturing or 3D printing is often used for creating models using a liquid photopolymer resin (resin). The models may further be used as casting molds, prototypes, patterns, or end products. 3D printing is able to create complex designs of a desired surface finish that may not otherwise be created through other machining or manufacturing methods. For example, stereolithography (SLA) casting molds may be used to manufacture turbine airfoils.
When 3D printing is used to create casting molds, the quality of the resulting component produced by casting is at least in part dependent on the quality of the model. The quality of the model is at least in part dependent on the quality of the resin. While the quality, including chemical and physical characteristics, of the resin is generally known prior to production of models, as the resin ages, chemical and physical characteristics of the resin alter toward depletion, in which the resin loses its ability to produce models. Depletion of the resin results in an increased occurrence of model crashes, in which the resin of the model fails to properly cure or harden, resulting in a loss of geometry, tolerances, or desired surface finish, and ultimately discarding of the model and the resin. Depletion of the resin often occurs before the entire quantity of resin is consumed (i.e. the useful life of the resin is expiring before the physical quantity of resin is consumed), thereby resulting in wasted resin, scrapped models, and increased costs.
Therefore, a need exists for a system and method for controlling chemical properties of a resin as the resin ages.